Experimental and computational investigations of a compact steam reformer for fuel oil and diesel fuel

The present work describes the optimisation of a compact steam reformer for light fuel oil and diesel fuel. The reformer is based upon a catalytically coated micro heat exchanger that thermally couples the reforming reaction with a catalytic combustion. Since the reforming process is sensitive to reaction temperatures and internal flow patterns, the reformer was modelled using a commercial CFD code in order to optimise its geometry. Fluid flow, heat transfer and chemical reactions were considered on both sides of the heat exchanger. The model was successfully validated with experimental data from reformer tests with 4 kW, 6 kW and 10 kW thermal inputs of light fuel oil. In further simulations the model was applied to investigate parallel flow, counter flow and cross flow conditions along with inlet geometry variations for the reformer. The experimental results show that the reformer design allows inlet temperatures below 773 K because of its internal superheating capability. The simulation results indicate that two parallel flow configurations provide fast superheating and high fuel conversion rates. The temperature increase inside the reactor is influenced by the inlet geometry on the combustion side.